After upgrading from 7.33 to 7.34, with AsynchDNS, requests to external sites now result in a hang with high cpu usage. Compiling without AsynchDNS does not exhibit this problem.
$ curl -v http://www.google.com/ * Hostname was NOT found in DNS cache * Adding handle: conn: 0x7fb11c007c00 * Adding handle: send: 0 * Adding handle: recv: 0 * Curl_addHandleToPipeline: length: 1 * - Conn 0 (0x7fb11c007c00) send_pipe: 1, recv_pipe: 0 * Trying 2607:f8b0:4007:803::1014... * Immediate connect fail for 2607:f8b0:4007:803::1014: No route to host ^C
Tested on Mac OS X 10.7.5 and 10.9.1
$ curl -V curl 7.34.0 (x86_64-apple-darwin11.4.2) libcurl/7.34.0 OpenSSL/1.0.1e zlib/1.2.8 c-ares/1.7.5 libidn/1.26 Protocols: dict file ftp ftps gopher http https imap imaps pop3 pop3s rtsp smtp smtps telnet tftp Features: AsynchDNS IDN IPv6 Largefile NTLM NTLM_WB SSL libz TLS-SRP
Bug was initially reported here: